Compensation of Temperature Effects on Guided Wave Based Structural Health Monitoring Systems
C.A. Dana,1, P. Kudela1, W. Ostachowicz1
1Polish Academy of Sciences, Institute of Fluid-Flow Machinery, Gdansk, Poland
Structural health assessment of structures based on ultrasonic piezoelectric sensors that have the capability to emit and record Lamb waves has developed greatly in recent years. The point has been reached where aerospace manufacturers can acquire complete off the shelf monitoring solutions composed of embeddable sensor networks, acquisition units and necessary software. Pre-established sensor networks can be fitted into composite structures opening the doorway towards permanent health monitoring and remaining service life assessment. In order to reach the desired higher levels of SHM (damage type, extent and life prognosis), strategies relying on a referential subtraction need to be utilized, . Although these strategies pay off in terms of higher level of insight into structural condition, they are highly sensitive to contamination from environmental factors like temperature or moisture. For structures operating under adverse environmental conditions, the process of subtraction between signals accounting for different states of the component induces an inherent noise caused by the changes in environmental elements. These factors affect the structure elastic properties, its density and they greatly affect excitation and sensing ability of transducers. Thus, in recent years a large effort has been put by researchers into the attempt to compensate these effects, . The work presented in this paper focuses on development of methods to compensate for the temperature effects on guided wave propagation.
Experiments and results
An experimental stand consisting of an aluminium plate instrumented with a rectangular SMART Layer was erected to observe the temperature effects on the damage detection capabilities of the proposed monitoring system, Figure 1.
Figure 1: Temperature measurements test stand
The particular features of this setup include large propagation distances (up to 0.7 m)...